The following computer-generated description may contain errors and does not represent the quality of the book:A turned period (•) placed after a vowel or consonant in any syllable indicates "stress;" that is, force. After the vowel it shews the vowel to be long, as bea•ting bee•ting. After the consonant it shews the vowel to be short, as batt•ing bat•ing. Every vowel may be long or short. Many other signs employed to indicate peculiar actions or sounds will be explained as the necessity for using them arises.

III. – The Nature of Musical Sound.

Sound. – Sound is a sensation due to a "vibration" of the air acting through the drumskin of the ear upon the terminations of the nerves of hearing in the internal ear.

Simple and compound vibration. – The vibration is said to be "simple" when each particle of air moves regularly to and fro like a pendulum. Any other vibration is called "compound," because it can be produced by the excitement of several simple vibrations at the same time.

Simple tone, and compound tone or note and noise. – A simple vibration produces a "simple tone." A compound vibration produces a "compound sound," which is a "note" or "musical sound" when every "double vibration" (or whole movement both ways) takes place in the same time; it is otherwise a "noise." The ear, by means of the numerous terminations of the nerve of hearing, "analyses" a compound sound, whether "note" or "noise," into the simple tones corresponding to the simple vibrations of which the compound vibration is, or may be, compounded. Every compound sound, whether note or noise, is therefore heard as if a series of simple tones were sounded in its place, and must, of course, be treated as a collection of simple tones. Those simple tones which collectively produce the audible effect of a note or compound sound are called its "partials."

Resonance. – Take an ordinary C or A tuning fork and an ordinary drinking tumbler, strike the fork and apply the end of it to the table in the usual way: the result is a slightly compound note. A note produced on a piano, violin, harmonium, or the human voice, is greatly compound. This means that the tuning fork note has few, and the other notes have many partials. Strike the fork again, and hold it with the flat side steadily over the mouth of the tumbler. It will generally be found that the tuning fork is inaudible. Then take the cover of a book, or even the outstretched hand, and gradually cover over more and more of the aperture of the tumbler. It will be found that the sound gradually increases in power as the aperture diminishes up to a certain amount, and then becomes weaker again, and that the deeper fork requires the smaller aperture to bring out its tone.